/Engine/Source/Developer/BSPUtils/Public/BSPUtils.h
Performs any CSG operation between the brush and the world.
static int32 bspBrushCSG ( [ABrush](API\Runtime\Engine\Engine\ABrush) * Actor, [UModel](API\Runtime\Engine\UModel) * Model, [UModel](API\Runtime\Engine\UModel) * TempModel, [UMaterialInterface](API\Runtime\Engine\Materials\UMaterialInterface) * SelectedMaterialInstance, uint32 PolyFlags, EBrushType BrushType, ECsgOper CSGOper, bool bBuildBounds, bool bMergePolys, bool bReplaceNULLMaterialRefs, bool bShowProgressBar )